Severe Thunderstorm Warning 277, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
235 PM CDT THU OCT 15 1998

...FORECAST CHALLENGES THIS TIME AROUND INCLUDE ALL THE ELEMENTS...

WARM FRONTAL BOUNDARY HAS BEEN LIFTING NORTHWEST THROUGH CENTRAL
NEBRASKA THE PAST SEVERAL HOURS AND SHARP THERMAL CONTRAST EXISTS FROM
NEAR SUX TO ONL TO A LOW JUST NORTHEAST OF LBF.  60 PLUS DEW PTS ARE IN
PLACE OVER SOUTHEAST NEBRASKA AS LOW LVL MOISTURE CONTINUES TO BE
ADVECTED NORTH.

MODELS IN DECENT AGREEMENT THIS CYCLE. NGM HAS FALLEN MORE IN LINE WITH
ETA/AVN ALTHO STILL WITH THE NRN BIAS ON LOW LEVEL FEATURES.  ETA AGAIN
THE MODEL OF CHOICE BECAUSE OF RUN TO RUN CONSISTENCY ALTHO NOT A LOT
DIFFERENT FROM AVN EXCEPT FOR A WEAK SHRT WV MOVG INTO THE AREA TNGT.
THE UPR LVL TROF CONTINUES TO DIG INTO THE GREAT BASIN AS LOW LEVEL
CYCLOGENIS TAKES PLACE OVER ERN CO INTO TNGT. LOW LEVEL JET ALREADY
INTO ERN NE AS 90KT 3H JET HEADS INTO WRN NE.

IN THE SHORT TERM BOTH ETA AND NGM BRING ANOTHER WEAK SHRT WV INTO THE
CWFA TNGT AND ISENTROPIC LIFT TOGEATHER WITH A WEAK SHRT WV HAVE
ALREADY PRODUCED TWO SVR WX EVENTS ACROSS THIS CWFA EARLIER THIS
MORNING AND ISENTROPIC LIFT REMAINS IN PLACE ON THE I305 SURFACE
THROUGH MOST OF FRI.  STRONG CAP IN PLACE IN THE WARM SECTOR SO WOULD
NOT EXPECT TSTMS TO FIRE UNTIL LATE TONIGHT AS CAP IS ERODED. ALONG AND
NORTH OF THE SURFACE BOUNDARY TSTMS ARE POSSIBLE THROUGH THE NGT AS UPR
LVL DIFFLUENCE MOVES INTO PLACE.  LOW LEVEL JET AND THETAE RIDGE EAST
OF CWFA BUT ENOUGH DYNAMICS IN PLACE FOR POPS OVER ALL. FOUS NUMBERS
CLOSE AND ACCEPTED. CONTINUED CHANCE OF SHWRS/TSTMS FRI OVER ALL OF
CWFA AS GOOD OMEGA FIELDS DEVELOP...PLENTY OF RH IN PLACE AND MAIN UPR
LEVEL SYSTEM BEGINS TO MOVE IN. SFC SYSTEM MOVES SLOWLY OUT OF NERN CO
INTO SWRN NE.  HUGE DIFFERENCES IN FOUS TEMPS ACROSS NRN NE AND WILL USE
SOMETHING IN THE MIDDLE.  NOT A LOT OF CHANGE FRI NGT ALTHO BOTH ETA
AND AVN LIFT SFC LOW RAPIDLY TO THE WRN GT LKS WITH COOL FRONT MOVG INTO
ERN NE. UPR LVL SYSTEM STILL IN PLACE AND WRAP ARND MOISTURE A GOOD
BET.  DRY SLOT FORECAST BY ETA AT 48HR NOT BOUGHT INTO BY AVN AND NGM
BUT NOT OVER THIS CWFA ANYWAY.  SNOW OR RAIN/SNOW NOT OUT OF THE
QUESTION OVER EXTREME NORTHWEST BY END OF PERIOD BUT WILL NOT MENTION
FOR NOW.

PRELIMINARY GUIDANCE FOR COORDINATION ONLY. OFFICIAL FORECASTS ARE
CONTAINED WITHIN PRODUCT OMAZFPLBF...

.LBF...NONE

CCF
LBF EW 050/065 041/055 027 3444
ONL EW 055/068 042/062 032* 4565
VTN EW 046/063 038/048 028 3455

BOWMAN